Machine tool control mechanism



M. E. MARTELLOTTI 2,349,595

MACHINE TOOL CONTROL MECHANISM Filed Dec. 9, 1940 4 Sheets-Sheet l ATTORNEY.

May 23 1944' M. E. MARTELLOTTI 2,349,595

MACHINE TOOL CONTROL MECHANISM Filed Dec. 9, 1940 4 Sheets-Sheet 2 75 77 llc@ 5 May 23, 1944, M. E. MARTELLoT-rl MACHINE TOOL CONTROLMECHANISM- Filed Deo.

9, 1940 4 Sheets-Sheet 3 ATTORNEY.

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M. E. MARTELL'OTTI MACHINE TOOL CONTROL MECHANISM Filed Dec. 9, 1940 TTORNEY.

iptented May 23, i944 Macnmn Toor. coN'mor. Mao:

Application December 9, 1940, Serial No. 369,204.

This invention relates to machine tools and more particularly to improvements in control mechanisms for governing the transmissions thereof.

The main object of this invention is to consolidate the control of the various adiusting elements of a milling machine transmission under a single lever which is selectively operable to change the feed rate or the speed rate; which is effective to stop relative movement between the tool and work when either of these changes is attempted during operation of the machine; and which is also eiective to dlsengage the main spindle clutch and cause operation of a power jogging mechanism which will slowly rotate the spindle transmission during speed changes therein.

Another object of this invention is to provide a control mechanism for eiecting speed and feed changes in a milling machine without a multiplicity of adjustments.

A further object of this invention is to provide an interlock between the speed change con- Other objects and advantages of the present.

invention should be readily apparent by reference to the following specification, considered in conJunction with the accompanying drawings forming a part thereof and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention. y

Referring to the drawings in which like reference numerals indicate like or similar parts:

Figure 1 is a side view of a milling machine embodying the principles of this invention.

Figure 2 is a diagram of the branch gear trains forl driving the feed and speed change mechanism.v

yFigure 3 is a sectional view through the column of the milling machine showing an expanded view of the spindle transmission.

Figure 4 is a diagrammatic view of the control mechanism of this invention.

Figure 5 is a detail sectional view of the spindle clutch mechanism. v l

Figure 6 is an expanded view of the feed transmission.

(Ci. 90-18l Figure '7 is a view of the feed rate change mechanism.

Figure 8 is a sectional view of the power jogger.

A conventional milling machine is usually 5 equipped with a spindle which is rotatable at variable rates for driving a circular cutter, and some form of work support which is relatively movable with respect to the cutter for feeding a work piece along a path tangentially thereto.

Due to the large number of variants entering into the question of economical machining of a given work piece, it is necessary to provide separate transmissions for thev spindle and work support so that 'either may be varied relative to the other to-yield a'variety of combinations from which to select the proper machining rate. Power operable means have Vbeen provided in the past changes must often be made in the midst of a machining operation, in which case a multiplicity of adjustments are now necessary in order to make the change.

For instance, the feeding movement must be stopped so that the work is not fed into a dead cutter, the spindle transmission should be' disconnected from its actuating prime mover to prevent gear clashing, and it is also desirable that a jogging mechanism be utilized to effect a slow rotation of the spindle transmission to facilitate intermeshing of the gears being shifted. By means of this invention the control elements for all of these functions, as well as the control of clutches which govern actuation of the feed and speed change mechanisms have been consolidatone direction to the speed change position will produce a predetermined sequence of events such as disengagement of the spindle clutch, power rotation of the selector valve, disconnection of hydraulic pressure from the selector valve during rotation thereof, actuation of a jogging mecha- /nism, and disconnection of the work support from its transmission to stop the feeding move-` ment. Return movement of the lever to neutral will reconnect pressure to the selector valve, efl fecting the desired gear shifts, reengage the spindle clutch after all gear shifts have been completed, stop the jogging mechanism and reconnect the work support to its transmission. When the lever is shifted to the feed change position, it

effects disconnection of the work support from its transmission, and power operation of the feed change mechanism. When the lever is returned, these operations are reversed.

In Figure 1 of the drawings there is shown a conventional milling machine having a column I uprising from a pedestal il the` column having vertical guideways I2 for supporting a vertically movable knee I3. The knee supports a saddle |4 for cross movement on guideways I5, and the saddle, in turn, carries a work support or table I5' which is movable parallel to the face of the column on guideways 'I4'. A cutter spindle I4 is journaled in the column for' rotating a cutter, such as I1 which may be supported by arbory I4. When the arbor is utilized, a pendant i4 is provided for rotatably supporting the outboard end of the arbor and the pendant, in turn, is supported from the column through an overarm 24.

The transmission for driving the cutter spindle I4 is more particularly shown in Figure 3 and comprises a. primary shaft 2| which is adapted to be driven by the prime mover 22 which in this instance is an electric motor. The motor is connected by the belt 23 for continuous rotation of a sleeve 24 supported by bearing 24' in the column I0, Figure 5. A shiftable clutch member 25 connects the sleeve for rotation of the shaft 2|.

The shaft 2| has a shiftable gear couplet 24 splined thereon comprising gears 21 and 24 which are alternately shiftableinto engagement with gears 29 and'30 fixed on a secondary shaft 3|. A second gear couplet 32 is also splined on the shaft 2| comprising gears 33 and 34 which are alternately shiftable into engagement with gears 35 and 35 respectively fixed on the shaft 3|.

A third shaft 31 has a spline gear couplet 34 thereon comprising gears 34 and 40 which are alternately shiftable into engagement with gears 35 and 4 I.

By means of these three sets of shiftable gear couplets it will be apparent that the shaft 31 may be driven at any one of eight different speeds.

A fourth shaft 42 is included in the spindle transmission and is reversibly connectible with the shaft 31 by means of a reversing mechanism comprising a pair of idler gears 43 and 44, a shiftable 'gear 45 splined on the shaft 31 and a gear 44 fixed with the shaft 42.

The gear 45 normally meshes with the gear 44 to eiTect one direction of rotation of the spindle I4 but when shifted to the left as view inv Figure 3 it disengages gear 44 and 'interengages the idler gear 43.

Since the idler gear 44 is in constant mesh with the gear 44 it will be apparent that this shifting will reverse the direction of rotation of the shaft 42. A gear couplet 41 issplined on the shaft 42 and consists of a large gear 44 and a pinion gear 49. When the couplet 41 is shifted to the right, the pinion gear 49 meshes with large gear 54 fixed with the spindle |4 whereby a seriesof low speed rates may be imparted to the spindle. When the couplet 41 is shifted to the left, the gear 44 intermeshes with a smaller gear 5| fixed with the spindle whereby a series of high speeds may be imparted to the spindle.

Actuation of the spindle transmission is controlled by the clutch 25 which has a shifter fork 52 supported on a shaft 53 and the shifter fork is oscillated by a piston 54 which, as shown in Figure `3, is connected by the piston rod 55 and link 56 to the upper end of the shifter lfork 52. The piston 54 is slidably mounted in a cylinder 51 and the admission of pressure to one end of this cylinder is controlled by a servo-valve. It will be noted from Figure 4 that one end of the cylinder 51 is connected by a channel 54 directly to the output of a pump 54. This pump has an intake 60 through which fluid is withdrawn from a reservoir 4|. The channel 54 has a branch 62 which is connected to a relief valve 43 whereby a predetermined pressure is maintained in the channel 54.

'I'he servo-valve includes a sleeve 44 which is slidably mounted relative to the piston rod in a bore 45 formed in the housing 44. This housing has a pair of spaced ports 41 and 43 which are in continuous communication with radial ports 44 and 14 formed in the sleeve. The piston rod 55 has an annular groove 1| in which a dia- A metrical hole 12 intersects an axial bore 13 formed in the rod and communicating with one end of vthe cylinder 51. The port y44 is continuously connected to the reservoir 4| by means of the return channel 14. It should now be obvious if the port 51 is under pressure with the parts in the position shown that this pressure will flow through the port 69 in sleeve 44 and the interdrilling in the piston rod to the left end of cylinder 41.

.This pressure will be substantially equal to pump pressure and since the area of the left end of piston 54 is larger than the area of the right end of the piston due to the piston rod the total pressure on the left end of the piston will he the greater, resulting in the piston being `moved to the right hand end of the cylinder. This movement eifects engagement of the spindle clutch 25.

The valve sleeve 44 is operatively connected by a bell crank 15 to a link 14, Figure, which is v pivotally connected to a crank arm 11. The crank arm is fixed on a shaft 14 which extends to the exterior of the machine where it is provided with a manual control lever 19, Figure l. When the control lever 14 is pushed upward to the position shown in Figure 1 it effects counterclockwise rotation of the crank 11 and thereby counterclockwise rotation of the bell crank 15. This shifts the sleeve 64 to the right, closing the port 14 'and opening the port 69, whereby pump pressure is yadmitted to the left end of cylinder 41 forcing the piston 54 to the right.

l When the sleeve is shifted to the left, the exhaust port 10 will be opened and the pressure port 44 closed, whereby the constant fluid pressure in the right hand end of cylinder 51 can now shift the piston 54 to the left, forcing the fluid in the left end of the cylinder to reservoir through the channel 14. This will effect disengagement of the clutch 25. Thus. the operation of the clutch 25 may be manually controlled through the servo-valve mechanism.

A power operable speed change mechanism is provided for shifting the gears of the spindle transmission and it comprises,` in general, a plurality of fluid operable gear shifters, a selector valve which has 16 stations per revolution, power operable means for rotating the selector valve, and a dial on the exterior. of the machine for indicating the current position of the valve. The gear couplet 24 is operatively connected by a pivoted shifter 40 to a fluid operable piston 4| slidably mounted in a cylinder 42.

25 has three positions, one of which is a neutral position which it assumes when the gear couplet 32 is in mesh. Likewise, the couplet 32 has a neutral position when the couplet 26 is in mesh. It is, therefore, necessary to provide means for centralizing the piston 8|.

This is accomplished The couplet the flanged sleeves engage shoulders 84 on the interior of the cylinder and shoulders 88 on the piston rod, thereby forcing the piston to a central position.

When pressure is admitted to only one end of the cylinder and the other end is connected to exhaust, vthe piston 8| will be moved either to the right or to the left to engage either gear 21 or gear 28 with its mating gear..

The couplet 82. is operatively connected by a pivot shifter 88 to a piston 81 which is slidably mounted in a cylinder 88. 'I'his piston is also capable of being moved. into three positions and the same means are provided for accomplishing this as was provided .furthe piston 8|.

'I'he couplet 88 is connected by a pivoted shifter 88 to a fluid operable piston 80 which is slidably mounted in a cylinder 8|. has two-positions. The gear couplet 41A is connected by a pivoted shifter 82 to a piston 98 slidably mounted in a cylinder 94. This piston also has only two positions. 'I'he ends of all of these cylinders are connected by separate channels to a selector valve indicated by the reference numeral 88. For instance, the opposite ends of cylinder 84 are connected by channels 88 and 81 t individual ports in the selector valve. The opposite ends of cylinder 82 are likewise connected by channels 88 and 88 to the selector valve while the cylinder 88 is connected by channels |80 andk lli to the selector valve.l

When one of these channels is connected to pressure and the other connected to exhaust both .of channels 88 and 88 are" connected to pressure whereby the couplet 28 is neutralized while the couplet 82 is in a motion transmitting position. Conversely when channel 98 or 88 is connected to pressurev while the other is connected to exhaust, both of channels |00 and |0| are connected to pressure whereby the couplet 82 is neutralized while vthe couplet 28 is in a working position.

The cylinder 8| is connected by channels |02 and |88 tothe selector valve. The selector valve is supplied with pressure from the pump 88 through an interlock control valve |84 which Yhas a pair of ports |88 and |08 which are normally interconnectedby an annular groove |81 in the plunger |88 of this valve. Thus, during the op- This piston only eration of the machine, fluid pressure is connected to all of the. cylinders in one manner or another in accordance withrthe position'of the selector valve to hold the gears in the` proper position to produce the desired' speed.

The-internal construction of the selector valve is not shown herein because such valves are known in the art and: the selector valve indicated herein may be of the same construction as that shown in U..S. Patent No. 2,012,081, issued August 20, 1935, and therefore specific description therelatter drives a clutch gear ||1 by means of gear ||8. The clutch gear is supported for free rotation on a shaft ||8 and has clutch teeth |28 which are engageable by clutch teeth |2| on the shiftable clutch member |22.

The clutch member |22 is splined on the shaft ||8 and normally held in a disengaged position by a spring |28. A pivoted shifter |24 serves to eect engagement of the clutch to drive shaft ||8 which is operatively connected through gearing |28 to the selector valve shaft |28. Since the clutch gear ||1 is continuously rotated by the prime mover it will be apparent that the selector valve may be actuated at any time whether the spindle transmission is running or not.

The shaft ||8 is operatively connected through gearing |21 for rotating the dial |28 located on the outside of the machine as shown in Figure l.

To facilitate intermeshing of the shiftable gears with the fixed gears a power jogging means has been provided for imposing a slow rotation on the spindle transmission during the time of gear shifting. Referring to Figure 5. the clutch member 28 which is operatively connected at all times to the shaft 2|, is provided with an internal conical surface |28 which engages a conical surface |88 on the brake member |8|.

When the spindle clutch is disengaged by the servomotor it is moved into engagement with the brake, thus producing a quick stop oi' the spindle. The braking element |8| is,'however. supported for rotation onv the bearing |82. It is provided with a ring gear |88 which intermeshes with a rack |84. The rack |84 is in eii'ect a piston rod which is operatively connected to a valve piston |88 which forms part of a power oscillator indicated generally by the reference numeral |88 in 4liigure 8.

, sure port and connected to channel |48.

The cylinder |41, in which the valve piston |88 reciprocates, is provided with a pair of spaced ports |48 and |48 which are connected by channels |88 and |8| respectively to ports |52 and |88 located in the extreme ends of the reversing valve housing as shown in Figure 4. The sleeve |81 is provided with two annular grooves |84 and |88 which are connected by radially drilled holes |88 to chambers |40 and |4| respectively. 'I'he interdrilled passages |88 and |81- terminate in ports |88 and |88 which are located at opposite ends of cylinder |41.

The other ends of these es terminate in ports |88 and which are properly positioned to be in continuous communication with the annular grooves |84 and |88 respectively.

In operation, the pressure fluid enters port |42 and with the valve sleeve to the left, as shown, it flows into chamber |4|, and through the' passage |81 to the right hand end of cylinder |41. This causes the valve piston |38 to move toward the left and rotate the gearing, Since the port |58 is connected to the exhaust portv |44, the piston |85 will move toward the left uncovering port |48 and port |48 in that order. The annular groove |82 will interconnect port |48 to an exhaust port |88 whereby the port |82 located in the right hand end of the sleeve valve housing will also be connected to reservoir. thus relieving any pressure on right end of the valve sleeve |81. When the port |48 is subsequently uncovered the fluid pressure will flow through channel |8| to port |08 applying pressure to the left end of the valve sleeve |81. The projected area of the end of the valve sleeve is greater than the end area of the plug |39 and therefore even although pump pressure exists in the chamber |4| the total pressure on the end of the sleeve will be greater causing the sleeve to move toward the right.

. As the sleeve moves toward the right it will restrict the opening of the exhaust port |44 creating a certain amount of back pressure in the chamber |40 which will act to assist the shifting movement and then when the pressure port |42 is opened to admit pressure to chamber I 40, the pressure will be further increased in chamber |40. This will tend to equalize or oiset the pressure in chamber |4|, leaving a resultant pressure on the end of the sleeve |31 which will complete the movement of the sleeve. Fluid pressure will now enter the left end of cylinder |41 through passage |58 causing movement of the valve piston |85 to the right. The ring gear |83 carries ratchet pawls |84 which engage a ratchet wheel |65 integral with the brake member |8| and positioned to be effective upon clockwise rotation of the gear |83.

This produces rotation of the shaft 2| in a direction opposite the direction it will be driven by the motor 22. This is necessary in order that when the braking load is placed on the brake member, it will move in a direction to transmit the load through the ratchet pawls to the piston which will be moved to one end of its cylinder to absorb the load.

The variable feed transmission is shown in Figure 6 and has a primary drive shaft |85. This shaft is driven from the constantly rotating shaft through gearing |61 as shown in Figure 2. The shaft |88 has a first couplet |88 splined thereon and comprising gears |88 and |10 which are alternately shiftable into mesh with gears |1| and |12 mounted on shaft |13.

A second couplet |14 is slidably splined on the shaft |66 and comprises gears |18 and |18 which are alternately shiftable into mesh with gears |11 and |18. The couplets |88 and |14 each have three positions, one of which is a neutral position whereby when one couplet is in a driving position the other is in a neutral position.

A third shaft |18 in the transmission has a couplet |80 splined thereon and comprising gears |8| and |82 which are alternately shiftable into mesh with gears |83 and |84 respectively .fixed on the shaft |13. By means of the three shiftable couplets |88, |14 and |80, the shaft |18 may be driven at any one of eight different speeds. The shaft |18 also carries fixed gears |85 and |88 which are alternately engageable by gears |81 and |88 of couplet |88 slidably splined on shaft |80. The shaft |80 has a gear |8| supported for free rotation thereon and in constant mesh with gear |82 supported for free rotation on the final output shaft |83. A shiftable clutch member |84 is slidably splined on the shaft |80 for connecting the gear |9| to the shaft |90. This clutch member serves to disconnect the` feed transmission from the final output shaft |83 whenever rate changes are made in the machine.

The final output shaft |83 may also be driven at a fast or rapid traverse rate through a rapid traverse gear train which is arranged in parallel with the feed transmission. This train begins With the gear |85 shown in Figure 2 and fixed to the constantly rotating shaft ||0. The gear |85 'I6 is connected through idler gears 88 and |81 to gear |88. The idler gears |88 and |81 are supported for free rotation on a sleeve |88 which also serves to Iiournal one end of the shaft |88 as more particularly shown in Figure 6.

The gear |88 intermeshes with a gear 200which is also supported for free rotation on the shaft |83. A feed rapid traverse selector clutch 20| serves to alternately connect the nal feed gear |82 or the final rapid traverse gear 20|) to the shaft |83 for alternate actuation of the work support at variable feed rates or at a rapid traverse rate. gearing 202 to a vertical drive shaft 203 which is operatively connected through any suitable known gear train for actuation of the Work support I5'.

The powerAoperable mechanism for shifting the various gears of the feed transmission to vary the output rate thereof is shown in Figure 7 and comprises four cams 204, 205, 206 and 201. The cam 204 has a cam groove 208 for receiving the follower 208 of a pivoted shifter 2|0 for the gear couplet |88. The cam 208 has a cam groove 2|| for receiving the follower 2|2 of a pivoted shifter 2|3 for the couplet |14. Likewise, the cams 208 and 201 have cam grooves 2|4 and 2|5 respectively for controlling the movements of Shifters 2|8 and 2|1 which are operatively connected to the gear couplets and |88. The cams 204 and 205 are fixed on shaft 2|8 and this shaft is driven from the shaft 2| 8 through gearing 220 which has a 1-2 ratio whereby the shaft 2|8 makes two revolutions for one revolution of shaft 2|8. The shaft 2|9, and thereby all the cams. are driven by the shaft 220 which is operatively connected to the shaft 2|8 through bevel gearing 22|. Referring to Figure 4, the shaft 220' has a clutch member 22|' fixed thereto upon which are formed clutch teeth 222 for engagement with clutch teeth 223 formed integral with the worm gear 224.

The worm gear 224 is actually held against axial movement and the shaft 220' is moved relative thereto to effect engagement ofthe clutch teeth. The worm wheel 224 is driven from the shaft |88 as shown in Figure 2 through spur gearing 225 and worm 226, the latter being supported on shaft 221 to which is attached one member of the spur gearing.

The shaft 220' has a shifter spool thereon and operatively connected by` a roller 228 to a pivoted shift lever 230. This lever has a ball-shaped end 23| which fits between the end of a plunger 232 of an interlock valve 233 and the end of shift lever |24. A spring 234 in valve |84 acting on the end of plunger |08 and a spring 235 mounted on the valve 233 and acting on the end of plunger 232 serve to maintain contact between the ends of the levers and the ends of the plungers at all times. l

A master feed-speed change control lever 233 is mounted on the exterior of the gear box 231 as shown in Figure 1 and this lever is keyed to the end of a shaft 238. The inner end of this shaft has a crank 238 keyed thereto andoperatively engaging the forked end 240 of the crank |24. It should now be obvious that counterclockwise rotation of the shaft 238 will effect clockwise rotation of the shift lever |28 causing engagement of the clutch |22 whlch'willdproduce power rotation of the selector valve 85.

This counterclockwlse rotation will also eiect shifting of the interlock valve plungers |08 and 232 toward the right as viewed in Figure 4. This The shaft |93 is connected by bevel v'm fixedl 26| of the clutch cylinder 66 to reservoir through channel 262 and interconnected ports 263 and 266 of valve |641. The port 266 is connected through a hydraulic resistance 265 to the exhaust channel 246. The higher pressure in the right hand end of cylinder 66 will shift the piston 56 and effect disengagement of the spindle clutch 25. Shifting of the piston 56 will effect interconnection of ports 261 and 266 and since the port 261 is supplied by the pump 59 uid pressure will ow through channel 246 to cylinder 250 to eect disengagement of the feed stop clutch |96. The cylinder 256 contains a piston fixed to the end of a shifter rod 252 which carries a shifter fark 256 which operatively engages the clutch member |96. A spring 256 serves to reengage the feed clutch when the piston 56 returns and interconnects the port 266 to exhaust port 255 by means of the annular groove 256 formed in the piston. 'I'he port 255 is connected to reservoir through channel 251, interconnected ports 256 and 266 of valve 233 and return channel 266.

Movement of valve plunger |66 will also close pressure port |05, and interconnect port |66 with port 26|. This will result in the supply line 262 of the selector valve being connected to the return line 266 causing a pressure drop in all the lines leading from the selector valve to the various shifter cylinders.

This also relieves internal pressure within the selector valve facilitating rotation thereof.

There is .an interlock between the speed change mechanism and the spindle clutch cylinder for the purpose of insuring that all gears have been fully shifted before the clutch is reengaged after a speed change operation. This interlock is in the form of a channel which runs serially through the selector valve and various gear shifter cylinders to the spindle clutch servo-motor. The selector valve supply line 262 forms the beginning of this channel. The channels 66 and 61 leading from the selector valve to shifter cylinder 66 constitute the next section of this channel. These two lines are alternately under pressure for shifting piston 93. The cylinder 96 is provided withv two ports 263'and 266 which are so located that one or the other will be open when the piston 66 completes a sluiting movement. For example, when the line 66 is con- These ports are alternately connectible to ports 26| and 262 by annular grooves 283 and 284 in piston 80. The ports 28| and 262 are connected by a common channel 286 to port 69 in the servo-valve sleeve 64.

It was stated in the description of the oper- 4ation of the servo-valve sleeve 64 that the port 61 was a pressure port. It should now be evident that rluid pressure is supplied to this port through the interlock channel just described. In other words, the pre^sure uid from the pump h6 flows through channel 56, branch line 286, interconnected ports |05 and |06 of valve |04, channel 252, selectively connectible ports in the selector valve whereby the fluid will continue through either channel 98 or 61, shifter cylinder 96, channel 265, one of the four annular grooves 116, 21|, 212 or 216 of shifter pistons 8|, 61, channel 216, one of the annular grooves 283,

mi 286 of shifter piston 66 and channel 285 to nected to pressure, the pistony 93 will be shifted l to the right and as the shifting movement is completed, the port 263 will be uncovered, whereby the fluid pressure which did the shifting will flow through port 266 to channel 265. Port 266 is also connected to this channel whereby when the piston 66 completes its shifting movement to the left, channel 61 will be connected to channel 265. It is through channel 265, that pressure fluid is supplied to the spindle clutch servo-motor and to the power logger.

The channel 266 is connected in parallel to four ports, two of which, 266 and 261, are in 5 shifter cylinder 62 and the other two, 268 and 266, are in shifter cylinder 68. The ports 266, 261, 266 and 266 are connectible by' annular grooves 216 and 21| in piston 6| and grooves 212y and 216 in piston 61 to ports 216, 215, 216 and 211 respectively. Only one pair of ports is interconnected at any one time. The fluid pressure from line 265 thus flows through one of the pairs of ports to channel 216 which terminate in ports 219 and 286 in shifter cylinder 9|.

port 61.

It should now be clear that the closing of port |65 and the opening of port 263 by the shifting of the interlock valve plunger |68 to the right in eiect cuts 0E the supply of fluid pressure to the port 61 and thereby to the left end of cylinder 61, and at the same time connects the left end of the cylinder to reservoir whereby the constant pump pressure acting on the right end of piston 56 through the port 261 is enabled to shift the piston 56 to the left and in spite of the iact that the servo-valve sleeve 66 remains in the same position. Thus, the spindle clutch is automatically disengaged even although the control lever 16 remains in a running position. The other et'l'ect produced by the shifting of the interlock valve plunger |06 is the creation of a hydraulic unbalance in the hydraulic oscillator by the interconnection of the channel 285 to reservoir through the connection of port |06 to the exhaust port 26|. y

In other words, the exhaust line |46 from the hydraulic oscillator which merges with the line 285 is open to reservoir so that the constant pump pressure which is always present at the port |62 may cause actuation of the oscillator.

It should now be evident that rotation of the master control lever 236 in a direction to cause counterclockwise rotation of the shaft 266 to produce a change in speed rate while the machine is running, stops rotation of the spindle through disengagement oi the spindle clutch, stops the feeding movement of the work support through disengagement of clutch |66, starts rotation of the selector valve and initiates actuation of the power jogging mechanism.

The operator watches the speed rate dial |22 and when the desired speed rate as indicated on the dial |26 registers with the arrow 261 he throws the lever 266 back to a neutral position. This immediately disengages the clutch 122 stopping rotation of the selector valve. yThey interlock valve plunger |08 will be delayed in re" turning by the choke coil 265. This will allow the pressure to gradually build up in the system to complete the shifting of gears as well as maintain operation of the hydraulic oscillator to the feeding of the work support may be resumed.

When the lever III is rotated in the Opposite direction to effect a change in the .feed rate the shaft III is rotated in a clockwise direction causing operative engagement of the clutch IIi' to drive the feed change mechanism and also cause shifting of the interlock valve plunger III. closlng port l and interconnecting P0115 25| with When the proper feed rate on the dial registers zo with the arrow III, the lever III is returned to neutral, disengaging the clutch III' and reengaging the clutch I Il.

Attention is invited to the fact that should a speed change operation be attempted when the spindle is not running, in other words, when the valve sleeve II is in the left hand position it will not interfere with the operation of the selector valve or the actuation of the power logging mechanism.

It simply removes the necessity of automatically shifting the piston N because it will already be in the proper position.

There has thus been provided an improved control u change a feed change may be effected in a milling e, and through interconnections with a master trol lever all the a 11;, incidental to effecting a change in 1. In a milling machine t having a prime mover and branch feed and speed transmissions for driving a work support and a tocl spindle respectively, the combination of feed and speed change control mechanisms associated with the respective branch transmissions, a control lever alternately shiftable to effect power actuation of said control mechanisms, a clutch normally positioned for operatively connecting the output of the feed transmission to the work support, and means operable by the lever when shifted to either power actuating position to effect disengagement of said clutch.

2. In a milling machine on having a prime mover and branch feed and speed transmissions for actuating a work support and a tool spindle retiveiv, the combination of feed and speed ons mechanisms associated with the respective issions, a control lever alternately table to enect power actuation of the respective mechanisms, a first clutch for connecting the prime mover to the speed transmission, a second clutch for operatively connecting by means of which a speed nately shiftable to eife'ct power actuation of the respective mechanisms, a clutch normally con-v necting the output of the'feed transmission for operation of the work support, a Jogging mechanlsm for the speed transmission, and means operable by the control lever upon movement to enect power actuation of the speed change control mechanism to effect disengagement of said clutch and power actuation of said jogging mechanism.

4. In a milling machine transmission having c. prime mover and branch feed and speed transmissions, the combination with feed and speed change control mechanisms associated with the respective transmissions, of a control lever having a ilrst position for effecting power actuation of the feed rate control mechanism, and a second position for effecting power actuation of the speed change control mechanism, a clutch for connecting the prime mover to the speed transmilon. a rit."- mechanism for the speed ton and me operable by the lever when in its ,t gagement of said clutch and power actuation of said jogging 5. In a milling transmission having a prime mover and branch feed and speed transmissions operable thereby for actuation oi a work support and a tool spindle respectively, the combination with feed and speed change control mechanisms associated with the respective transmissions, of a control lever having a iirst position for effecting power actuation of the feed rate control mechanism, and a second position for effecting power actuation of the speed change control mechanism, a first clutch for connecting the feed transmission for operation of the work support, a second clutch for connecting the speed ton to the prime so mover, a jogging mechanism for the speed transthe output of the feed on for actuag5 prime mover and branch feed and speed transmissions for enecting actuation of a work support and a tool spindle respectively, the combination with feed,` and speed change control m with the respective branch traons, of a control lever altermission, means operable by the lever when shifted to its first position to effect disengagement of one of said clutches, and additional means operable by the lever when shifted toits second position to ensei; disengagement of both of said clutches and power actuation of said Jogging mechanism.

6. In a milling machine having a spindle transmission and a speed change control mechanlsm therefor, the combination with a source of power and a clutch for connecting said source of power for actuation of the` transmission, of manual control means for engaging and disengaging said clutch, a control lever shiftable to effect power operation of said speed change control mechanism, and additional means operable by the control lever to eifect'dlsengagement of said clutch and to prevent reengagement by said manual control means during operation ot the speed change control mechanism.

7. In a milling machine having a spindle transmission and a speed change control mechanism associated therewith, the combination tion for effecting disen-` the speed of said trission incluv the spindle 1 t r, 1.-. i. during actuation of the "i .ce control mech.

c. In a milling machine having a feed transmission for actuating a work support, and a speed transmission for actuating a tool spindle, the combination with means for changing the speed of said spindle transmission, oi' a control lever shiftabie to eil'ect power actuation of 'said means, and means operable by the lever to render the feed transmission inoperable for actuating the work support during actuation 01' said speed changing means.

9. In a milling machine having a feed transmission for actuating a work support and a speed transmission for actuating a tool spindle, the combination of a stop clutch in the feed trission, power operable means for chansind the ratev of either transmission including a selector control lever, and means operable by the lever when shifted to either of its operative positions to eect disengagement oi said stop clutch.

l; In a milling machine, the combination with a variable speed transmission for 1` spindle, a prime mover and a clutch for #on necting the prime mover for actuation of the transmission. ofa speed change control mechanism associated with the tr l sa huid oparable means for actuating said clutch including a manual control lever, a second control lever for effecting power actuation oi said zw change mechanism, and means controlled by the last-named lever to eii'ect iiuid shifting of said clutch independent of the manual control lever.

11.111 a milling machine having s spindle transmission, a prime mover and a clutch for connecting the prime mover for operation of the transmissiomthe combination oi' a speed1 chance 1 mechanism for said transmission including a se-l lector valve and a plurality oi' huid operable shifters connected thereto, a Huid operable actuator for said clutch, a control lever shiitable to edect power positioning of said selector valve, a

www: 'shaving a spindle on', a n mover and a clutch for cluding a servo-valve having two positions, power actuators for sluiting the gears of said transmission. a pressure line serially connected through a tool control valve associated with said lever having y a source of pressure connected thereto, channel means connecting said selector valve and of said fluid operable Shifters in series between said control valve and said duid operable actuator whereby when said control valve is positioned bv the lever to connect the source of pre to said channel means the clutch shifter will not omrate until al1 oi' said iluid operable have completed their` movement.

12.111 a milling machine ha a n transmission, a prime mover :11M a clutch fo connecting the prime mover for actuation of transmission, the combination of a duid w piston tor actuating said clutch, ci s r holding said'piston in a clutch d f1 sition, a speed che mec :il :w for l ity of uid operable scar shifters, a source of pressure, a first control valve for said piston, channel means connecting said source of pressure in series through said nuid operable shifters to the control valve, means for positioning said control valve to eifect shifting o! said 1m-l to a clutch engaging position, a control lever for governing power operation of the i: cl-.il change mechanism, and a second valve means ses.. 1- ated with said lever for disconnecting the source rof pressure from said first-named control valve during actuation of the speed change mechanism whereby said piston will eect disensemcnt of said clutch during operation of the il mechanism.

, spindle clutch will said actuators to the servo-valve whereby said valvevis inenective until all Shifters are in a final position, a control valve insaid pressure line for stopping the now oi pressure to said servo-valve during operation of said shii'tcrs, and means for shifting said piston to a clutch discugin positiiln when the pressure is disoonnccm by said v ve.

li. In a milling m having a spindle tron, a prime mover and a clutch for connecting the prime mover for operation of the traion, the combination of a servo-motor i'or operating said clutch including ya servo-valve, a plurality ol huid operable shifters for changthe of said i :o a selector i controlling the shifters to be oper ing power positioning of said selector valve, a control valve lated with said lever, channel means connecting said control valve, said selector valve. said shii'tersjand said servo-valve in series in the o er named whereby when pressure is disconnected from said selector valve the disengaged, and when pressure is v f v `f to said selector valve said clutch will be engaged after all of shifters have their una] position.

i. in a milling machine having a spindle n a prime mover vand 'a clutch for connecting said prime moverl to the transmission, the combination of a iluid operable piston for actuating said clutch, a source of pressure 'connected to one side of said Piston for continuously urging the piston in a direction to disconneet said clutch, a speed change' :f for said tran including a plurality of fluid Ioperable shitters and a selector valve for determining and controlling selective operation of said shifters, a duid ble device for actuating the 1: to a e of presacted to s return line, i u power actuation t. actor v ve, a control valve. channel l: for w i l :il said control valve serially through the ector ve and said huid oper- Wm di Los... n.181 t0 th@ Othl Side 0f d clutch piston and to said return'line, means in control ve for connectinga source of pressure to said ce1 means to age the clutch e., stop e 1a device, Vand means to shift t control valve m res N r to lever movement i means to rmervoir `whereby the ciu h will be disengagedand the device will be energized to enect actuation oi' the pmdle i im, rn; 16.,In a milling machine having a work support and a tool support, the combination of driving means therefor including a prime mover and branch feed and speed tr l w spective supports, a rst clutch for disconnecting the speed transmission from the prime mover independent of the feed transmission, a second clutch for conn cting the output of the feed transmission to t work support, a ieed change mec i a and a speed ce mechanism associated with the respective branch transmissions,

It it i connecting said plime mover for operation of control leverior determin-y a control lever having a neutral positionand alternatelyshiftable thereirom--to effect power operation of the respective .mechanisms said` speed change mechanism including a plurality of uid operable Shifters and' a'.s'eiector; valve, fluid operable means clutches including a piston for shifting the firstnamed clutch, channel meansv connecting theselector valve and fluid operable Shifters in series with said piston. a control valve normally connecting pressure to said channel means, said control valve being responsive to movement of the lever in one direction from neutral to connect said channel means to reservoir to eiec't shifting of the rst-namedpiston,l and means controlled by said piston for connecting pressure to the second-named piston.

17. In a milling machine having separate power operable rate change mechanisms for the variable feed transmissions-of the machine, and a common prime mover for said mechanisms and transmissions, of a common rate change control 'lever movable to definite positions on opposite sides of a central position for selectively connecting said mechanisms for operation by the prime mover to change the rate of the respective transmissions, fluid operable control clutches ior rendering each transmission drivingly effective, a selector valve and a jogging mechanism for the rate change mechanism of the variable speed transmission, a common hydraulic control circuit operatively connected to said clutches, selector valve and jogging mechanism, means responsive to movement of the rate control lever to its speed change position for disconnecting pressure from said circuit whereby said selector valve may be rotated without pressure connected thereto and said transmissions will be rendered drivingly ineiective during rate change operations and said jogging mechanism will be rendered effective to slowly drive the speed transmission to facilitate for actuatingAv each of :said:v

gear sl'iif'ting when pressure is connected to the shiftablegears by the selector valve, and means responsive to completion of the gear shifting operation to stop operation of the jogging mechanism.

18. n a milling machine having separate power operable rate change mechanisms for the variable speed and variable feed transmissions of the ,machine and a common prime mover for said mechanisms and transmissions, of a common rate change control lever, movable to definite positions on opposite sides of a central position for selectively connecting said mechanisms for opto change the rate control clutches for rendering each transmission drivingly eiective, a selector valve and a jogging mechanism for the rate change mechanism of the variable speed transmission, a common hydraulic control circuit operatively connected to said clutches, selector valve and jogging mechanism, means responsive to movement of the rate control lever to its speed change position for disconnecting pressure from said circuit whereby said selector valve may be rotated without pressure connected thereto and said transmissions will be rendered drivingly ineilective during rate change operations and said jogging mechanism will be rendered effective to slowly drive the speed transmission to facilitate gear shifting when pressure is connected to the shiftable gears by the selector valve, means responsive to completion oi the gear shifting operation to stop operation of the jogging mechanism, and a second valve means responsive to movement o! the rate change control lever to its feed change position to eiect disengagement of said clutches and thereby render said transmissions drivingly ineffective during operation of the feed rate changing mechanism.

MARIO E. MARTELLO'ITI. 

